This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-085108, filed Mar. 24, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a method of manufacturing a semiconductor device, and in particular to a method of forming a pattern on the surface of a semiconductor wafer substrate.
The process of manufacturing a semiconductor device comprises a number of patterning steps which are performed by depositing a plurality of materials as a processing film (i.e. film to be processed) on a silicon wafer, the resultant deposited layers being subsequently patterned into desired patterns. The patterning of these processing films is performed as follows.
First of all, generally, a photosensitive material called resist is deposited on a processing film to form a resist film, a predetermined region of which is then subjected to an exposure. Thereafter, this exposure region or non-exposure region of the resist film is removed by subjecting the resist film to a developing treatment to thereby form a resist pattern, which is then employed as an etching mask in the dry etching of the processing film.
As for the exposure light source to be employed in this exposure step, ultraviolet rays such as KrF excimer laser and ArF excimer laser are generally employed in view of enhancing the throughput. Due to the recent trend to further enhance the microfabrication in the LSI however, the resolution which is now demanded is so high that the fineness thereof is smaller than the wavelength of the ultraviolet rays, so that it now becomes difficult to sufficiently secure the exposure process tolerance (or process margin) such as the tolerance in exposure value, focus tolerance, etc. While it may be effective for the purpose of making up for this process margin to make thinner the film thickness of the resist film to thereby improve the resolution, if the film thickness of the resist film is made thinner, it will lead to another problem that it becomes difficult to secure a sufficient thickness of resist film that is required for the etching of the processing film.
In view of overcoming this problem, there is proposed a method using multi-layer resist as disclosed in Solid State Technology, 26(5), 105(1983), wherein a lower film, an intermediate film and a resist film are successively deposited on a processing film, then, a lower film pattern is formed by transferring a resist pattern via the intermediate film to the lower film, and finally, the processing film is processed using this lower film pattern as an etching mask.
According to this method, the lower film is required to be useful as an etching mask, so that the lower film is required to be constituted by a material which can be hardly sputtered and includes a large number of carbon atoms excellent in etching resistance. However, since a material having a high content of carbon atoms is poor in gas permeability, a source gas or part of the source gas tends to stay between the lower film and the intermediate film on the occasion of etching the lower film with the intermediate film pattern being used as an etching mask, thereby giving rise to the generation of phenomenon that the intermediate film tends to be expanded and ruptured. Therefore, it has been very difficult to properly work the lower film.
An object of the present invention is to provide a method of forming a pattern, which is capable of processing the lower film without inviting the rupturing of the etching mask formed on the lower film, even if a material having a high content of carbon atoms is employed for the lower film.
According to the present invention, there is provided a method of forming a pattern comprising the steps of;
forming a lower film on a substrate, the lower film being a film containing carbon atom at a ratio of 80 wt % or more, or a vapor phase deposition film;
applying an adhesion-promoting treatment to a surface of the lower film;
forming an intermediate film on a surface of the lower film on which the adhesion-promoting treatment has been applied;
forming a resist film on the intermediate film;
forming a resist pattern by conducting a patterning exposure of the resist film;
forming an intermediate film pattern by transferring the resist pattern to the intermediate film; and
forming a lower film pattern by transferring the intermediate film pattern to the lower film.
According to the present invention, there is also provided a method of forming a pattern comprising the steps of;
forming a lower film on a substrate, the lower film being a film containing carbon atom at a ratio of 80 wt % or more, or a vapor phase deposition film;
applying an adhesion-promoting treatment to a surface of the lower film;
forming a resist film containing a metal atom or a semiconductor atom on a surface of the lower film on which the adhesion-promoting treatment has been applied;
forming a resist pattern by conducting a patterning exposure of the resist film; and
forming a lower film pattern by transferring the resist pattern to the lower film.
According to the present invention, there is also provided a method of forming a pattern comprising the steps of;
forming a lower film on a substrate, the lower film being a film containing carbon atom at a ratio of 80 wt % or more, or a vapor phase deposition film;
forming an adhesion-promoting film on a surface of the lower film;
forming an intermediate film on a surface of the adhesion-promoting film;
forming a resist film on the intermediate film;
forming a resist pattern by conducting a patterning exposure of the resist film;
forming an intermediate film pattern by transferring the resist pattern to the intermediate film; and
forming a lower film pattern by transferring the intermediate film pattern to the lower film.
According to the present invention, there is also provided a method of forming a pattern comprising the steps of;
forming a lower film on a substrate, the lower film being a film containing carbon atom at a ratio of 80 wt % or more, or a vapor phase deposition film;
forming an adhesion-promoting film on a surface of the lower film;
forming a resist film on a surface of the adhesion-promoting film;
forming a resist pattern by conducting a patterning exposure of the resist film; and
forming a lower film pattern by transferring the resist pattern to the lower film.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.